RE: VOIP

From: Joe Martin (joe@xxxxxxxxxxxxxx)
Date: Sun Mar 24 2002 - 20:56:26 GMT-3


   
On the loopback interface of each router add the command:

Router(config-if)# h323-gateway voip bind srcaddr <ip_address>

For the IP address, use the loopback address. This will take care of it
for you and will also solve some one way voice issues that can occur.

Joe
CCIE#5917

-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
Lupi, Guy
Sent: Sunday, March 24, 2002 3:04 PM
To: 'ccielab@groupstudy.com'
Subject: VOIP

I have VOIP set up and working, I have it configured so that the voip
peer is the other routers loopback address. I was assuming therefore
that the source and destination addresses of the packets between the 2
routers would be the loopback addresses that are configured, but that is
not the case. When debugging ip packets, I found that the source and
destination was actually the IP address of the interface that the
packets are being forwarded out of and received on. See below, can
anyone tell me why this happens, and if there is a way to force VOIP
traffic to use a particular IP address, other than using NAT? If not,
will the VOIP traffic always be sourced with the IP address of the
interface on which it leaves? Thanks.

R7
!
dial-peer voice 2 voip
 destination-pattern 8888
 session target ipv4:8.8.8.8
!
dial-peer voice 1 pots
 destination-pattern 7777
 port 1/0/0

R8
!
dial-peer voice 1 pots
 destination-pattern 8888
 port 1/0/0
!
dial-peer voice 2 voip
 destination-pattern 7777
 session target ipv4:7.7.7.7
!
access-list 199 permit udp any any

r8#debug ip packet detail 199

(Here I placed a call from r8 to r7)

00:01:48: IP: s=2.8.2.8 (Null0), d=2.7.2.7 (Serial0/0), g=2.8.2.2, len
60, forward
00:01:48: UDP src=17272, dst=16762
00:01:48: IP: s=2.8.2.8 (Null0), d=2.7.2.7 (Serial0/0), g=2.8.2.2, len
60, forward
00:01:48: UDP src=17272, dst=16762
00:01:48: IP: s=2.7.2.7 (Serial0/0), d=2.8.2.8 (Serial0/0), len 60, rcvd
3
00:01:48: UDP src=16762, dst=17272
00:01:48: IP: s=2.8.2.8 (Null0), d=2.7.2.7 (Serial0/0), g=2.8.2.2, len
60, forward
00:01:48: UDP src=17272, dst=16762



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